The present invention relates to radiation burners. Such burners are utilized in chemical, oil processing and oil chemical industries, in metallurgy and other areas where it is necessary to provide an indirect radiation heat exchange.
One of such radiation burners is disclosed in Soviet Inventors' Certificate No 954,079. The burner includes an injector with a gas nozzle, a regulating disc, a cylindrical outlet member provided with a reflector and accommodated in a recess of a burner stone fixed in a casing which is arranged with a gap relative to the rear wall of the stone. The above described burner, similarly to other burner devices, has the disadvantage in its low degree of blackness of the refractory burner stone, which at the temperature of 1,520.degree.-1,550.degree. K is approximately 0.3-0.4. This degree of blackness determines a certain density of the heat flow which cannot be increased without the artificial increase of the degree of blackness of the refractory material. Another disadvantage of this burner is that it is not possible to suppress the formation of nitrogen oxides which are quite substantial in the waste products of combustion at temperature of 1,520.degree.-1,550.degree. K. The ejection of the fuel gas from the burner nozzle with a high speed produces high noise which is another disadvantage of the known burner.
Other radiation burners of this type are disclosed for example in U.S. Pat. No. 3,664,424 and French Patent 2,195,328. The radiation burner disclosed in these references includes an injector with a gas nozzle, the burner head and a movable slider. The burner is mounted in a recess formed in a ceramic block which forms a part of the furnace wall. In accordance with another embodiment, the section of the burner which extends outside of the outer surface of the furnace wall is enclosed in a casing provided with a mounting plate which is fixed with a gap to a steel outer plate of the furnace. The casing is provided with a noise-absorbing lining which is held by a perforated sheet. The burner head has a plurality of peripheral longitudinal openings for passing of a prepared gas-air mixture. In order to provide the high quality combustion of the fuel gas of changing content, the burner is provided with air suction of a secondary air. This burner similarly to many otherflow burners has the disadvantage that its construction does not permit substantial increase of its output without the increase of its size. For this reason if the minimal output is to be increased three times, it is necessary to replace the injector and the gas head. The second disadvantage of this burner is that it does not permit a high quality flame-free combustion of the fuel gas, since the burner head is located at a substantially great distance from the surface of the ceramic block, and the gas-air mixture which ejects through the longitudinal openings in the burner head in a substantially thick layer does not completely burn at the surface of the furnace wall. As a rule, the final combustion takes place inside the furnace, which leads to an incomplete combustion and excessive consumption of fuel. Finally, a further disadvantage of the burner is that the suction of the secondary air for increasing the combustion degree of fuel gas is obtained only due to the modification in the furnace combustion chamber. This makes is regulation very difficult. The insufficient quantity of air leads to a chemically incomplete combustion and environmental loading with products of incomplete combustion. If the optimal demand for air is exceeded, this leads to the increase in losses with ejected combustion products and ejection of toxic gases.
A new gas burner was proposed in U.S. patent application Ser. No. 07/985,854. In the radiation burner disclosed in this patent application, combustion products are recirculated through passages provided in the burner stone, in order to reduce the combustion temperature and reduce the contents of nitrogen oxides in the combustion products. It is advisable to further improve the radiation burner of this type.